Roll support hubs are known to be used on automatic, semi-automatic, and manual apparatuses from which roll products are to be dispensed or applied. Moreover, it is known to provide a friction braking mechanism which acts against the rotation of such a roll support hub so that the tension of the material dispensed can be controlled and to prevent over-rotation of the roll when demand is ceased.
Adhesive tape dispensers and applicators are one type of device which typically requires a roll support hub. Many types of tape dispensers and applicators are known depending on the area of use, for example: for industrial packaging lines, store packaging and wrapping, or in an office environment. Typically, the purpose of these type tape dispensers is to facilitate the use of the tape from such a dispenser, and to do so in accordance with the specific application.
Manual tape dispensers are typically used in small packaging departments and, as well known, typically consist of a roll support hub which rotates on a support axle or bolt which is projected from a support base that may be equipped with a handle. Other conventional features include guiding mechanisms and cutting mechanisms. Such roll support hubs are known to include a braking system, normally comprising a controlled friction braking system, with its primary purpose to regulate the rotation of the tape roll. The braking system, of such known tape dispensers, includes on one side of the roll support hub a friction surface in a perpendicular plane to the axis of rotation which is fixed with the roll support hub and rotates with the roll support hub around the support axle and by a sliding pressure disc that is axially slidably mounted to the support axle and on which operates an adjustable spring. The braking action is determined by the amount of pressure of the spring applied to the pressure disc which is frictionally engaged with the friction surface of the roll support hub.
A typical set-up of a roll support hub that is provided as part of a manual tape dispenser is shown in FIG. 1. A roll support hub 1 is illustrated and which is rotatable about a support axle 2 which is in turn fixed with a tape dispenser support 3, again which is typically provided with a handle and a cutting means. Such support axles 2 are typically secured to the support frame 3 to be non-rotational, such as by a rivet shown at 4. The hub 1 includes a bearing 5 which is rotational on the support axle 2. On the side of the roll support hub 1 away from the support frame 3, a shoulder 6 is provided extending from the bearing 5 and which provides a friction surface that is in a general plane perpendicular to the axis of the support axle 2.
At the other end of the support axle 2 from the support frame 3, a non-circular portion 7 of the support axle 2 extends above the plane of the friction surface of the shoulder 6. By this, a pressure disc 8 having a corresponding opening is supported to be axially slideable on the non-circular portion 7, but rotationally fixed with the support axle 2. A knob 9 is adjustably mounted to the support axle 2, such as by a bolt 10 so that the distance between the lower surface of the knob 9 and the upper surface of the pressure disc 8 can be adjustably defined. Between the lower surface of the knob 9 and the pressure disc 8, a compression spring 11 is provided which provides a biasing force against the pressure disc 8 toward the friction surface of the roll support hub 1.
Between the pressure disc 8 and the friction surface of the shoulder 6, a friction disc 12 is also provided. The friction disc 12 is typically rotatable about the non-circular portion 7 of the support axle 2. As can be seen, the rotatable roll support hub 1 rotates about the fixed support axle 2. As the roll support hub 1 rotates, its shoulder portion 6 experiences relative movement between itself and the non-rotational pressure disc 8. The compression spring 11 provides the force against the pressure disc 8 which increases the friction between the surfaces of the pressure disc 8, the friction disc 12, and the friction surface of the shoulder 6. By adjustment of the knob 9, the force generated by the compression spring 11. can be controlled so as to increase or decrease the friction between the aforementioned elements. By this, a controlled friction can be applied to the roll support hub 1 to regulate the rotation of the roll hub support 1 and thus the dispensing of material from the roll.
This set-up, as mentioned above, is at present almost universally used; however, certain deficiencies exist. The ring-shaped friction disc, and the friction surfaces on the pressure disc 8 and the shoulder 6 are considerably reduced so that, to obtain a sufficient braking force, it is necessary to use a particularly strong compression spring 11 that is adjusted to provide a heavy load. A first specific problem is that the braking action under such a heavy load can be difficult to control, which can frequently result in dispensing with too much or not enough braking action. Additionally, it is a problem that the edge of the bearing 5 of the roll support hub 1 that is adjacent the support frame 3 is pushed against the support frame 3 with a force that is so strong that it causes a rapid wearing of the base portion of the bearings. Referring again to FIG. 1, in order to deal with this latter problem, it is known to provide a sleeve 13 at the base portion of the bearing 5, although this clearly adds to the complexity of the manufacturing and increases costs of production. Normally, the roll support hub 1 is made of a plastic material, such as polypropylene, which is relatively ineffective against wear. The sleeve 13 can be made of a material that is more effective against wear, for example Delrin.TM., which is extremely effective against wear and tear, but is substantially more expensive.